Tuning mechanism



Nov. 15, 1949 1 M, AMMERMAN y 2,488,366

l TUNING MEcHANIsM Filed June 29, 1948 f nventor [4 fra E!! 4 r 'yZ 20X f5 i fs Patented Nov. 15, 1949 PATENT OFFICE Jbiijginmmer'man, oak Bark, nl., assign'or to Radiov Corporation of America, a corporation ofDelaware Application June 29, 1941's, Serin No; 35,769

2 Claims. l

This invention pertains to atni'ng mechanism for a radio,'and more particularly' to a radio tuner of novel construction and arrangement of parts requiring a reduced pressure to operate the mechanism.

It is a primary object of the present invention to provide a V"novel tuning mechanism which has a minimum number "of movable parts, is simple in construction, economical to' manufacture and utilizes a reduced pressure for purpose of operation.

Another object of the invention is to provide a tuner mechanism for sequential operation of station selection employing a core carriage assembly which carries a selector shaft with stop lobes for individual station selection and ratchet turning and stop means'.

A further object`r of the invention is to provide a spring loaded' core carriage having novel stop and adjustment means forre'storing the core carriage after actuation to its next predetermined positioning means for signal' reception.

A further object' of the'invention is to provide a spring loadedv corevcarriag'e having novel means for manual and sequentialtunin'g which may be actuated either electricalljzas by a solenoid, or

by a manually' operable push'button forsequen'tial tuning with an independent control for tuning over a continuous range offr'equency.

Further andV other objects'of the invention may be, and may become apparent," from apersal of the disclosure herein.A It is'l to be understood that while certain specificl illustrations are presentedfthey are noty t`o be considered" as limitations e'cept as' defined bythe spirit of the appended claims.

In the drawings:

Fig'. 1 isl a plan vview of the tuner, partially broken away',v showing the core carriage in position for signal reception from one of the preselected stations. y I

Fig. 2 is a side view taken along lines 2-2 of Fig. 1, showing the core carriage and sequence advancing mechanism just before completing an advancing step in the sequence.

Fig; 3k isv a' plan-'view off-'the tunerk showing manual and electrical means connected to the operating linkage system carried by the cover of the supporting structure.

Fig. 4 is an end view of the cam shaft showing only the ve cams spaced equidistant thereon in relation to one of the cam stops disposed on a cam shaft positioning screw.

Referring to the drawings, there is shown a radio tuning mechanism II having a supporting (Cl. 74-10L15) structure consisting', of front and rear-'plates I2 and I3y respectively, side plates I4 and I5 respectively, a base plate I6,Y and4 a cover plate I1. Three tuning coilsin housingsv shownfat I8, are secured to the rear plate I3 by screws I'9i, and have terminals for electrical lconnections to the associated radio receiver circuits.

Tuning cores 2i! are movable within the coils, and are connected by means of tuning wires? 23 and adjusting screws 22 to a core carriage assembly frame 24 which is movable for-effecting simultaneously shifting of all the coresk 2l)A within their respective coils.

The core carriage assembly frame' 24 is an L-shaped member which rides at one end thereof on a guide rod 25, whichl guide rod is rigidly secured to the front and rear plates of the supporting structure. The core carriage assembly frame is maintained in axial relation with the guide rod 25 by holes formed at opposing ends of the short leg of the L-shaped core carriage assembly frame. A selector shaft- 2B is heldin relation to the core carriage assembly frame by being positioned inf an aperture disposed in the 25" short leg of the L-shaped core carriage assembly frame with one end of said shaft being movably mounted in an aperture formed in the area 23 of the core carriage and protrudes beyond the side plate I4 and rides to and fro in the supporting structurevia a slot 29 formed in the side plate I4. A ratchet stop wheel 30 and aA ratchet turning wheel 3I are disposed on the shaftZ. Five stop lobes or dogs, four indicated by 32 and the fifth by 32 are equiangularly spaced in a spiral around the shaft 26, the four lobes 32 being used" for engaging their respective limit nuts 33 for sequence operation, the lobe 32 being used with a limit nut 33 for manual tuning.

vA ratchet stop finger 34 is pivota-lly' mounted by a pin 35 on the supporting structure, and a spring 35 urges the ratchet stop nger 34 against the ratchet stop wheel 30 which rotates in the direction of arrow X, as shown. A ratchet turning ringer 35 is pivoted on a pin 36"Which is conl nected to the supporting structure, and engages the ratchet turning wheel 3| undery inuence' of a' spring 3l. In the position shown in Fig. 2"the core carriage has been moved to the right almost as far as it will go and the turning finger 35' has rotated the wheel 3| and selector shaft 26 almost completely around to the next step of the selector sequence. A little further movement of the core carriage will cause the shaft to rotate far enough for the stop nger 34 to slip behind a ratchet tooth of the ratchet stop wheel 30, and keep the 3 shaft 26 from turning back to the last step position upon return of the core carriage.

The limit nuts 33 have their lower portions movably mounted in slots 40 formed in the base plate I6 of the supporting structure, while the upper portions of the limit nuts have shoulders 4I which are engageable by their respective lobes or dogs 32.

Positioning screws 43 have opposing ends pivotally mounted in the front and rear plates of the supporting structure and are held against longitudinal movement by collars 44 and 45 which are secured adjacent opposing ends of said positioning screws. A manual positioning screw 46 is similar to screws 43, and is disposed in relation to the supporting structure in the same manner as the positioning screws 43. A manual tuning knob 8 is used for manual tuning when the cam 32' is in engagement with its respective limit nut 33. Limit nut 33 is disposed on the manual positioning screw 46 with one portion thereof protruding through a guide slot in the side plate I in a similar manner as the other limit nuts are guided in the slots 46 formed in the base plate.

There is a limit nut 33, a positioning screw 43, v

and a lobe 32 foreach of four positions of the core carriage, representing a possibility of four selective radio stations which may be tuned in through sequence operation. A cylindrical stop 48 is disposed on the guide rod 25 to limit the extreme movement of the core carriage assembly frame 24 under influence of the retractile spring 49 connected between the front'plate I2 and a pin 5U on the core carriage assembly frame 24, said retractile spring core carriage toward the front plate I2 of the supporting structure so that the lobes 32 may engage their respective limit nuts 33, or the lobe 32' may engage the manual positioning screw nut 33'.

The upper edges of the front, rear and side plates by means of screws 41. A push button 5I secured to a, push button arm 52, somewhat C-shaped in cross section, and slidable back and forth on a push button lever guide 53 secured to the cover plate I1. An operating lever 54 is pivoted to thel push button lever 52 by a pivot pin 55. One end of the operating lever 54 is pivoted to the cover plate by a pivot pin 56. The opposite end of the operating lever is pivoted by a pin 51 to an operating link 58, the `opposite end of said link being pivotally connected to the link stud 59 secured to the core carriage. The link stud is disposed to ride in the cover slot 63; Inward pressure on the push button in direction of the arrow Y will cause the core carriage to be moved rearwardly, and release ofpressure on the push button will cause the retractile spring 49 to urge the push button and the core carriage to its forward position as limited by one of the cams on the cam shaft and its respective cam stop.

Thesolenoid 1 is shown by legend to be connected to a control circuit so that an electric push button may be connected in any convenient or conventional manner to operate the tuning mechanism in lieu of themanual push button 5I.

49 constantly urging the.

cover plate I1 is xedly secured on theV CTX r Number In order to set-up or adjust the tuner for preselected signal reception, the operator sequentially operates the tuner until the desired stop lobe is in engagement with its complemental limit nut. Rotation of the particular limit nut positioning screw will then permit the core carriage to be moved until the desired station is properly tuned in. Thereafter that particular lobe and limit nut engagement, during sequential operation of the tuner, will cause the same station to be again tuned in.

From the foregoing presentation it will be seen that the tuning means may be varied in sequential operation for signal reception of preselected sta- .tions by'successive actuations of the lobe carrying core carriage. Further, one of the lobes may be positioned by sequential operations of the core carriage, to engage a manually operable positioning screw for effecting tuning over a continuous range.

What is claimed is:

l. In a preselectable sequence tuner device: housing structure; a positionable tuning element slidably mounted with respect to the housing structure for controlling the tuning in accordance with its position; a rotatable selector shaft pivotally carried by the tuning element, and eX- tending at an angle to the sliding direction of the tuning element, said shaft having a plurality of outwardly extending helically disposed stop lobes; a corresponding plurality of limit nuts individually held in the path of the respective stop lobes to limit the travel of the tuning element in one direction; sequencemechanism connected to the tuning element for moving it in the opposite direction in ,response to a sequence manipulation, and for automatically returning the element in said one direction when the sequence manipulation is completed; said sequence mechanism also including stepping elements connected for rotating the selector shaft one rotatory step during each to and fro movement of the tuning element to bring a different one of the lobes in position for engaging its limit nut to cause the tuning element to stop its return movement at predetermined positions; rotatable preselection screws each having longitudinally spaced portions pivotally held directly by Said housing and threadedly carrying one of the limit nuts; and slots in the housing receiving said nuts and guiding them for threaded adjustment along their screws.

2. The combination as defined by claim 1 and including at least one additional slot in the housing for guiding the selector shaft and tuning element in their to and fro sequence movements with respect to the housing.

JOHN M; AMMERMAN.

REFERENCES CITED Name Date 2,305,326 Swallow a Dec. 15, 1942 

